The choice of fabric dyeing and finishing process is mainly based on the specifications of the fabric, finished products and other requirements, which can be divided into bleaching, dyeing and finishing. At present, many factories still have a semi-continuous state in smelting and bleaching production. The singeing alone, the use of cold rolling piles or desizing and bleaching alone, the cold rolling pile has protection for the strength of the fabric, etc., but 24 hours of stacking affects the production efficiency There are also problems such as difficulty in cleaning up the piled ground. Therefore, the combined pre-processing of the decoiling and bleaching process is superior to the batch processing in terms of environmental protection, energy saving and high efficiency, which can save labor and improve production efficiency. A decoiling and bleaching combined machine can have three workers, and the production speed can be controlled at 90～ 110m/min, compared with the batch type, the efficiency is greatly improved. This article focuses on the continuous pre-treatment process and process.
Author: Jeong Se-wide, Master of Management Science and Engineering, Qingdao University, Shandong Anqiu Bachelor dyeing
Natural fibers contain impurities. In the process of textile processing, various slurries, oils and contaminated dirt are added. The presence of these impurities not only hinders the smooth processing of dyeing and finishing, but also affects the performance of fabrics.
The purpose of training and bleaching is to apply chemical action to remove impurities on the fabric, make the fabric white, soft, and has good permeability, and prepare for dyeing and finishing.
1. Introduction of continuous pre-processing equipment
Cloth feeding device → bristle box → singeing machine → water washing box → chemical tank (chemical automatic control system) → steaming box → water washing box → drying device → cloth output stacking device → cloth rolling device → mercerizing machine →Heat setting machine (the picture is for reference only, each factory can add water washing boxes before and after the two steamers according to their own needs to meet their own production needs).
2. Process introduction
Original cloth preparation → feed cloth → singeing → desizing → scouring → bleaching → drying → rolling.
2.1 Original fabric preparation
Original fabric preparation includes original fabric inspection, fabric turning and stitching. The purpose of the original fabric inspection is to check the quality of the grey fabric and find that the problem can be solved in time. The inspection content includes two physical indicators and appearance defects. The former includes the length, width, weight, warp and weft yarn density and density, strength, etc. of the original cloth, and the latter includes spinning defects, weave defects, various stains and damage. After the original fabric inspection, the original fabric must be divided into batches and printed on the head of the fabric to indicate the variety for easy management. If the production is produced in the own factory, the inspection of the embryonic fabric can be omitted, and the weaving factory will inspect the above items.
In order to ensure continuous batch processing, the original fabric must be stitched. The stitches at the joints should not be too dense or too thin. Too dense can easily cause joint marks during winding, and too thin to break the cloth.
2.2 Bristles, singeing
The purpose of singeing is to burn off the fluff on the cloth, make the cloth smooth and beautiful, and prevent uneven dyeing and printing defects caused by the fluff during dyeing and printing. The singe of the fabric is to quickly pass the open width of the fabric through a high-temperature flame. The singeing opening usually has two positive and two opposite sides. It is selected according to the thickness of the fabric. Usually, the thin cloth has one positive and one reverse. anti.
At this time, the fluff present on the fabric quickly heats up and burns, but the fabric itself is relatively tight and the temperature rises slowly. When it has not reached the fire point, it has left the flame, so that the fluff can be burned without burning the fabric. the goal of.
2.3 Desizing
Textile mills often sizing warp yarns for smooth weaving to improve strength and wear resistance. The slurry on the grey fabric not only affects the water absorption performance of the fabric, but also affects the quality of the dyed and finished products, and will increase the consumption of dyed chemicals. Therefore, the slurry should be removed before scouring. This process is called desizing.
The slurry on the fabric is usually PVA starch slurry, which is characterized by being easily soluble in hot water above 80°C, so most of the slurry can be removed before scouring. PVA slurry is difficult to degrade and easily cause Environmental pollution, the slurry returned by hot water can be collected together for recycling, the recovered PVA can continue to be used in the weaving factory, and the PVA recovery device can reduce the pressure of sewage treatment and save costs.
2.4 scouring
When cotton fibers grow, natural impurities (pectin, waxy substances, nitrogen-containing substances, etc.) accompany them. After the cotton fabric is desizing, most of the slurry and some natural impurities have been removed, but there are still a small amount of slurry and most of the natural impurities remaining on the fabric. The presence of these impurities makes the surface of the cotton fabric yellower and has poor permeability. At the same time, it greatly affects the appearance quality of cotton cloth.
Therefore, it is necessary to cook the fabric under the action of high temperature concentrated alkali and some auxiliary additives to remove residual impurities. Scouring is the use of caustic soda and other scouring aids to chemically degrade or emulsify and puff the pectin, waxy substance, nitrogen-containing substance, and cottonseed husk, etc., and remove impurities from the fabric after washing with water.
